FIVE NEW COMBINATIONS AND ONE NEW NAME IN RUBIACEAE FROM SOUTH-EAST ASIA

Taxonomic studies in the Rubiaceae by Bridson (1987) and Davis & Bridson (2004) enumerate species for which new combinations are needed. Herein we take the opportunity to propose five new combinations and one new name (nomen novum), as based on the aforementioned studies, viz. Cyclophyllum caudatum (Valeton) A.P. Davis & Ruhsam, C. longiflorum (Valeton) A.P. Davis & Ruhsam, C. novoguineensis (Miq.) A.P. Davis & Ruhsam, C. valetonianum (S. Moore) A.P. Davis & Ruhsam, Psychotria montisgiluwensis A.P. Davis & Ruhsam, and P. montisstellaris (P. Royen) A.P. Davis & Ruhsam.


INTRODUCTION
Taxonomic studies in the Rubiaceae by Bridson (1987) and Davis & Bridson (2004) enumerate species for which new combinations are needed.Herein we take the opportunity to propose five new combinations and one new name (nomen novum), as based on the aforementioned studies, viz.Cyclophyllum caudatum (Valeton) . caudatum, C. longiflorum, and C. valetonianum), all from New Guinea, potentially requiring new combinations in Cyclophyllum.In addition, we have identified another member of the Vanguerieae from New Guinea, Plectronia novoguineensis (Miq.)Valeton, which should be placed in Cyclophyllum.Canthium caudatum and C. longiflorum have also been placed in Plectronia L., but the use of this generic name has to be restricted to the family Oliniaceae, as Plectronia is a generic synonym of Olinia Thunb.(Ross, 1975: 491;Verdcourt, 1987: 127).Plectronia was formerly used in the Rubiaceae as the generic name for a large number of species, mostly belonging to the tribe Vanguerieae and in particular Canthium.
There are only two genera of Vanguerieae in New Guinea: Cyclophyllum and Psydrax Gaertn., although the informal group Pyrostria 'group B' was recognised by Bridson (1987).Pyrostria 'group B' is a group of taxa that may either constitute a new genus or perhaps a disjunct part of Pyrostria (Bridson, pers. comm.).In New Guinea Pyrostria 'group B' is confined to the Kepala Burung (Vogelkop Peninsula), in the extreme NW part of the island.A key separating Cyclophyllum and Pyrostria 'group B' is given by Bridson (1987: 614).
The morphological differences separating Cyclophyllum and Psydrax are considerable, and they can be easily separated on the basis of easily definable morphological differences (e.g.see Reynolds & Henderson, 1999: 354).According to molecular data provided by Lantz & Bremer (2004: 263) Cyclophyllum is convincingly associated with the 'dioecious Pyrostria group', and Psydrax is a well-supported monophyletic unit.
Canthium does not occur in New Guinea, although several taxa from New Guinea have been placed in the genus.On morphological grounds their placement is erroneous (Bridson, 1987), a fact that is supported by molecular data (Lantz & Bremer, 2004).
We propose that three Rubiaceae species currently placed in Canthium and one in Plectronia should be transferred to Cyclophyllum: Cyclophyllum caudatum, C. longiflorum, C. novoguineensis, and C. valetonianum.The two type specimens bearing flowers (for C. longiflorum and C. valetonianum) have the salient characteristics of Cyclophyllum after Bridson (1987: 616): paired bracts absent; inflorescence fasciculate or occasionally with rudimentary inflorescence branches; corolla always hypocrateriform; style widening at apex; flowers hermaphrodite; ovary 2-locular.The two type specimens bearing fruit (C.caudatum and C. novoguineensis) possess the first two characters listed above and they have the characteristic elongated pedicel of Cyclophyllum.Specimens matching C. caudatum and C. novoguineensis held at the Kew herbarium (K) possess the floral characters of Cyclophyllum, as listed above.
One new combination and one new name are proposed.Note -The new name P. montisgiluwensis is proposed because the name P. giluwensis is already being used in Psychotria (P.giluwensis Sohmer).